Tuesday, March 30, 2010
Not all diamonds that are found on Earth originated here. A type of diamond called carbonado that is found in South America and Africa may have been deposited there via an asteroid impact (not formed from the impact) over 3 billion years ago. These diamonds may have formed in the intrastellar environment, but as of 2008, there was no scientific consensus on how carbonado diamonds formed. Presolar grains in many meteorites found on Earth contain nanodiamonds of extraterrestrial origination, probably formed in supernovas. Scientific evidence shows that white dwarf stars have a core of crystallized carbon and oxygen nuclei. The largest of these found in the whole universe so far, BPM 37093, is located 50 light-years (4.7×1014 km) away in the constellation Centaurus. A news release from the Harvard-Smithsonian Center for Astrophysics described that the 2,500-mile (4,000 km)-wide stellar core as a diamond.
Labels: Extraterrestrial formation
posted by Tamil Nadu ,Tamilnadu Government,Places,Wild Life,Hill Stations,Temples,Sports,Accomodation,Cusine,Fine Art @ 12:11 AM
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Monday, March 8, 2010
Being a form of carbon, diamond oxidizes in air if it is heated over 700 °C. In the absence of oxygen, for e.g. in a flow of high-purity argon gas, diamond can be heated up to about 1700 °C. Its surface blackens, yet it can be recovered by re-polishing. At high pressure diamond can be heated up to 2500 °C, and a report published in 2009 suggests that diamond can withstand temperatures of 3000 °C and above.
Labels: Thermal stability of Diamonds
posted by Tamil Nadu ,Tamilnadu Government,Places,Wild Life,Hill Stations,Temples,Sports,Accomodation,Cusine,Fine Art @ 9:23 PM
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